How Do I Cut, Fit, and Install a New Liner?

  1. Be sure the MIG Gun is laid out and arranged in a straight line. The guns casing must be free from twists when installing or removing a wire liner. .
  2. Remove the old liner by first removing the MIG gun’s contact tip.
  3. Pull the old wire liner out of the conduit/casing assembly from the feeder connector (feeder adapter plug end). If you are using a feeder adapter that has an Inlet Guide, the inlet must be removed first. If you have any problems removing the liner you may un-thread the feeder adapter first. This will also back the liner out of the conduit/casing.
  4. Make sure you have a good sharp cut off blade for nylon liners and a sharp side-cutters for steel liners. A dull cutoff tool can change the shape of the liner and make it hard to insert or remove from the liner from the gun. It can also create a feeding issue by scratching or deforming the wire.
  5. To get the correct length of the new liner, insert the new liner into the feeder adapter and feed it through the conduit/casing, through the gun body.
  6. If using an inlet guide, make sure to install the inlet guide on the feeder adapter.
  7. Once again be sure the MIG Gun cable is arranged in a straight line, free from twists, when installing a new wire liner.
  8. Sometimes on longer conduits/casings and liners it may take 2 people; one on each end to rotate and twist the conduit/casing to get the liner through the torch body.
  9. If you have any troubles getting a liner through a torch, double check you have a good sharp cut off. If needed, you can gently sand the end of the steel liner on a belt sander. For nylon liners we use a 60-degree chamfer tool to remove the sharp cutoff edge. You can remove the cast in the aluminum liner by pre-bending gently against the cast and straightening the liner before loading.
  10. After the new liner comes out the end of the torch, you want to cut the new liner off flush with the end of the copper gas nozzle (copper gas cup). ***Before cutting the liner; if using an inlet guide; make sure to gently push the liner back into the feeder adapter to feel you have removed all gaps. This is very important to ensure you have the correct length, as you do not want any gaps between the liner and the tip in the gun.
  11. If you do not have an inlet guide on the feeder adapter; it is very important to ensure that the liner is seated in the feeder adapter. It is important to understand how the feeder adapter goes into the wire feeder as you do not want any extra unwanted gaps that could cause feeding issues.
  12. Now you have cut and determined the overall length of the liner, you still must cut and take out the length of the contact tip, plus your tip set back (or the position you are running the tip in). Normal welding position for steel and aluminum is an 1/8” set back from gas cup to contact tip. For cored wire we do have a series of tips with a 3/8” set back.
  13. Carefully remove the liner one more time. If you need to you can use the tip to push the liner backwards. If using an inlet guide, make sure to first remove the inlet guide or you cannot push the liner backwards
  14. After removing the liner hold the gun end of the liner up and hold the contact tip up against the liner end
  15. Cut off the liner the length off the tip, plus the set back of the tip (1/8” or 3/8” tip setbacks).
  16. Now that you have cut off the liner the length of the tip plus the tip setback, you may install the new liner. It will back up into the back of the tips 60-degree chamfer or concave. Always make sure you have a good sharp cutoff.
  17. We always recommend checking the condition of the insulation tube in the front of the torch and collet nut that holds the slip-in tip (if using).
  18. Always blow out the front of the welding gun when changing a liner, gas nozzle or contact tip.
  19. We always recommend replacing the spatter disc/gas diffuser, contact tip, insulation tube, and nozzle, after installing a new liner.
  20. You may tighten the flat head set screw in the inner body, or the Allen set screw in the docking spool body onto the conduit/casing to prevent backward movement or an unwanted pumping action of the casing. If you back the set screw off just a little, you can allow for the casing/conduit to rotate in the gun without pumping.
  21. If you need to secure the set screw from coming loose it is recommended to use the blue Loctite.